David Mills, the estranged husband of the culture secretary, Tessa Jowell, has said it was "entirely his idea" to split from his wife and that he hopes they will get back together when the furore over his alleged bribe from Silvio Berlusconi subsides.

In his first interview since the couple announced their separation, he insists that his "tremendous friend" Alistair Campbell played no part in the decision. "I was simply being used as a stick to beat my wife with and the only thing to do was to remove the stick," he told Legal Business magazine, published tomorrow. "It's awful. I hope that with peace and privacy, and time, things will return to normal, but we've both been through the most ghastly trauma. She's in India and Australia at the moment, but we're in touch."

Despite the trauma, he describes the saga as "very exciting". "It's like a thriller, all of this," he said.

Mr Mills also says that he thinks he may have the extra piece of evidence that will help him show that an alleged bribe from Mr Berlusconi was actually money paid to him by another businessman.

"By sheer chance, the most extraordinary chance last night, I discovered a piece of clinching evidence that the money came from Diego [Attanasio]. It's virtually the final piece in the jigsaw. It takes me from 97.5% to 99%."

Mr Attanasio, a shipping magnate who served time in an Italian jail for corruption, has repeatedly denied that he gave Mr Mills the money.

Italian investigators, who have asked for Mr Mills and Mr Berlusconi to be committed for trial on corruption charges, contend that the payment was a bribe from the Berlusconi empire.

Mr Mills, an international lawyer who acted for both Mr Attanasio and Mr Berlusconi, added: "I have 15 pieces of evidence and need one more to establish that the $600,000 came from Diego Attanasio."

Mr Mills traces his troubles back to a payment of £2m from Horizon, a Berlusconi company for which he acted when he was at his former law firm Mackenzie Mills. He regarded the payment as a "windfall" for him but says he had intended to give £50,000 or £100,000 to each of his three partners. However, Mackenzie Mills was being wound up and merging with the City law firm Withers.

Although he says he had kept his partners out of the Berlusconi business, the other partners insisted on treating the payment as partnership profits, leaving Mr Mills with less than £500,000 and "a bitter taste in my mouth".

He says he had "taken a big risk and had been put in the front line of the Berlusconi trials". So he was "pissed off" when his partners "took money from Horizon, which was a Berlusconi company".

It was this that Mr Mills says he was referring to in a letter to his accountant Bob Drennan, which has been seized upon by Italian prosecutors.

The accountant reported the letter, which argued that the "gift" should not be taxable, to the National Criminal Intelligence Service. Mr Mills later said the letter was setting out a hypothetical scenario and that the money came not from Mr Berlusconi but from Mr Attanasio. He tells Legal Business: "You have to understand that the letter is more like a novel. There are a lot of facts, but some fiction."

He adds: "I admit that it was convoluted and stupid, and has got me into an awful lot of trouble. The whole thing has exploded in my face in the most ghastly possible way."